1. Field of the Invention
The present invention relates to a liquid discharge head for discharging a liquid and a process of producing the liquid discharge head. More specifically, the invention relates to a process of producing a liquid discharge recording head for conducting recording by discharging, for example, an ink to a recording medium.
2. Description of the Related Art
An ink jet recording head is known as a liquid discharge head for conducting recording by ejecting droplets from discharge ports. In some ink jet recording heads, foams are formed by a liquid overheated by receiving thermal energy, and droplets are discharged from the discharge ports of the ink jet recording head by the effort of this generation of foams. The discharged droplets adhere to a recording member to record information. Such an ink jet recording head includes an ink-discharge-energy-generating unit for generating ink discharge energy disposed on a substrate; an upper protection layer for protecting the ink-discharge-energy-generating unit from ink; and a lower layer for storing heat. When the ink discharge energy is heat, the ink-discharge-energy-generating unit is usually a heating element.
Furthermore, the ink jet recording head includes a coating resin layer serving as a passage wall constituting a passage, and this passage wall is provided with discharge ports.
A method of producing the above-described ink jet recording head is disclosed in U.S. Pat. No. 6,390,606.
In the method described in U.S. Pat. No. 6,390,606, a positive photosensitive resin layer is formed on a contact layer made of resin provided on a substrate, and a pattern having a shape of passage is formed by patterning the positive photosensitive resin layer. Furthermore, a negative photosensitive resin layer serving as a passage-forming member is formed on the upside of the positive photosensitive resin layer and the contact layer. Discharge ports are formed in the negative photosensitive resin layer, and the pattern having a shape of passage is removed to complete the formation of the passage.
In the method described in U.S. Pat. No. 6,390,606, when the positive photosensitive resin layer is provided on the contact layer, materials for these layers have to be selected such that the positive photosensitive resin layer does not damage the contact layer, so that the reliability of the adhesion of the control layer with the passage-forming member may not be affected by the damage. Therefore, the selection of a material for the positive photosensitive resin layer or the contact layer will be regulated.